Firstly, I like to give credit to [k] / kinaed who wrote this article, first published in bdwf forum, so I'm only extracting my contribution, and just the introduction with respect to the main author. You can read the rest of the article @ http://www.bdwf.net/forum/showthread.php?t=70940" onclick="window.open(this.href);return false;
191-ЧС ВМФ Водолазом/Navy Diver
The Златоустовский Часы Завод/Zlatoustovski Watch Factory (ЗЧЗ), in Zlatousт, Chelyabinsk Oblast, Russia, was created from the industrial awakening of the Soviet Union. The city of Zlatoust was founded in 1754 in support of the ironworks plant located near the Ay River, 160 kilometers west of Chelyabinsk. By the early 19th century, Zlatoust was known for it's production of bulat steel sabers carried by cavalry and military officers of all Imperial services, as well as the earliest steel cannon's and artillery indigenously produced for the Imperial Army.
The Soviets gained control over Zlatoust in 1918, and transformed the city into a center for metallurgy, mechanical engineering, tool-making, and other industries. Because of it's industrial prowess, Zlatoust became the site of the relocated First Moscow Watch Factory (1МЧЗ) in 1941. After the 1МЧЗ moved back to Moscow in 1943, the Zlatoustovski Watch Factory continued production of Type-1 based wrist and pocket watches.
Beginning sometime in the 1950's (and ending sometime in the 1960's), production began on the Водолаз/Vodolaz (Diver) - also known as the Тритон/Triton (Merman). Commissioned by the Special Design Bureau of Timing Mechanisms, which was established for the development of new designs of special instruments of time, program time and other devices, the Triton was the preliminary dive watch produced in the Soviet Union, and used exclusively by hard hat divers.
With a diameter of 60mm and height of 20mm, the piece is very large and meant to be worn outside a pressurized divers suit, as shown in the image below:
A gasketed canteen-style screw-down crown cover is employed to ensure pressure integrity at depth. Several variations exist, including the gasket systems employed as seen in these two variations below:
Movement
The movement for these pieces was based on the tried and true 15-jewel Type-1 movement made famous by the 1МЧЗ, but produced at Zlatoust, and bears the "ЗЧЗ" factory symbol on the train bridge/bottom plate. Updated with a mono-metallic balance wheel, Bregeut overcoil and brass wheel train, the 191-ЧС is a very robust and accurate movement.
Later in the production cycle, the 191-ЧС was slightly revised to include a unified escape wheel/fourth wheel cock:
The open up case of my Zlatoust Diver
Dive Kit
The Triton was issued along with several other pieces of equipment necessary for hard hat diving; the diver's kit included an underwater compass, a depth gauge, and a knife and scabbard (not shown):
The Г-5 depth gauge is capable of measuring up to 50m:
The КНМ compass has a small air bubble to prevent pressure mounting when in use. The bubble is also used to level the compass by directing the bubble to the circle drawn on the top of the compass: